1. Field of the Invention
Embodiments of the present invention relate to the measurement of biological signals, and more particularly, to methods, media, and apparatuses measuring biological signals using a multi-electrode module, and a lead search method using the multi-electrode module, by which biological signals such as electrocardiograph (ECG) or heart rate (HR) can be measured regardless of the attachment location of the multi-electrode module and the arrangement directions of electrodes.
2. Description of the Related Art
Typically, in connection with medical appliances, electrodes are attached to particular positions of the human body to make a diagnosis. The electrodes are manufactured by interfacing different elements. A signal wire interconnects an analyzer instrument and metallic or conductive electrodes are attached to desired positions on a patient's skin. The combination of a wire and an electrode will be called a lead. Currents generated from the heart in the chest flow along the surface of the skin and produce a voltage difference between two electrodes attached to the skin. One of most available diagnosis tests using the electrodes attached to the human skin is the ECG. A general ECG measurement uses 12 lead positions to provide the most accurate signals for detecting variations of the ECG caused by ischemia. For the ECG measurement using the 12 lead positions, it is necessary to attach 10 electrodes to various positions on the patient's body and the limbs to analyze ECG data. 12 records on the ECG are read from first through ninth leads, with the tenth lead being used as a ground. Among the ten electrodes, six electrodes are applied to the patient's chest and remaining 4 electrodes are applied to the limbs according to predetermined anatomical landmarks. Usually, the electrodes applied to the chest are expressed as V1, V2, V3, V4, V5, and V6, respectively, and correspond to precordial leads. The electrodes applied to the limbs are expressed as LA, RA, LL, and RL (ground), respectively, and correspond to limb leads.
In order to obtain accurate and reproducible records, it is very important to accurately position the precordial leads. However, it is difficult to accurately arrange and attach these plurality of leads. Therefore, such a cumbersome operation consumes too much time and requisite knowledge, techniques, and efforts of a person attaching the electrodes. Often, the leads are not appropriately arranged and/or even attached in slightly lower or higher positions, thereby generating bad ECG data. On the other hand, a periodical ECG test is important to provide ECG profiles of the patient for early detection and diagnosis of cardiovascular diseases. For providing accurate ECG profiles, it is required that the electrodes be arranged in the same positions they were located in the previous test. The electrodes must also be securely fixed.
Unfortunately, according to the conventional ECG measurement technique of using 12 lead positions, the locations of attaching 6 precordial leads are nearly the same for every patient in spite that the locations of different patient's hearts being slightly different from each other. Therefore, it is difficult to make an accurate diagnosis. Furthermore, since 6 precordial leads have are often attached at slightly deviated locations every periodical ECG test, accuracy and reliability for persistent management of ECG data have been degraded.
To overcome such shortcomings, a multi-electrode module has been developed by integrating a plurality of electrodes into at least one module. However, it is also difficult to accurately identify the attachment location of the electrode module. Moreover, since the polarity of the active signal of the heart electricity may be changed depending on the arrangement directions of the electrodes, unskillful general users may feel inconvenienced.